Allendale County, SC Shrink-Swell Risk

What Allendale County, SC's soil means for a foundation

Low

USDA's SSURGO data puts Allendale County, SC's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 1.02% across 97.8% of the county's surveyed land. Among the 3,144 counties on this site, that's the clean result: little shrink-swell movement, standard construction the likely outcome.

This is a county figure, not a lot figure

USDA's survey covers the whole of Allendale County, SC at once, not any single address. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Allendale County will actually do.

Report cost vs. repair cost

With Allendale County, SC rating "Low", a geotechnical report is still worthwhile before a build, just less urgent than in a high-risk county. A geotechnical report runs $1,000-$5,000, typically around $2,700. Foundation repair, if a specific lot turns out to differ from the county average, runs $5,000-$15,000.

How Allendale County, SC compares

Nationally, Allendale County, SC is the 2,892-most-constrained of 3,085 rated counties for shrink-swell soil. Within South Carolina alone it ranks 45 of 46. Allendale County, SC is 408 square miles with a population of 7,551.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Marion County, IA and Terry County, TX are worth a look for comparison.

How this reading is built, and its real limits · Moisture management: the cheap fix that works on any soil

More of South Carolina

Every county in South Carolina is on this site, including Charleston County, SC and Greenville County, SC. The full underlying dataset is downloadable directly, one row per county.